Method of and apparatus for processing continuous discrete batches of particulate product

Abstract

A trough-type watertight drag conveyor for particulate material to be processed commences initial stages of the processing while the material is still within the trough. More specifically, in one significant application of the invention, treating liquid is utilized during the processing, this liquid serving further to assist in the conveyance and thereby minimize potential damage to certain materials. Paddles dragged along the trough essentially dam the material in relatively discrete batches. Despite being isolated in batches, the product flow is continuous, the batches being separated only by the thickness of the paddles. Conveyor speed is controlled to allow sufficient residence time of the material within the treating liquid in those instances where required. The paddles are restrained against lifting from the trough bottom to maintain a fairly intimate seal between the trough and paddles. The treating liquid is extracted from the material prior to discharge from the conveyor, and in its preferred form, the treating liquid is recirculated and reused.

1 . The method of conveying a particulate product immersed in treating liquid and extracting the liquid from the product during the conveyance, comprising the steps of: 
 a. providing an elongated horizontal stationary watertight trough having a product and liquid inlet end, a product discharge end remote from the inlet end and a liquid extraction section intermediate said inlet and discharge ends, said trough having a bottom wall and opposing upwardly and outwardly-extending side walls for the length thereof;    b. providing an articulated continuous conveyor within the trough, which conveyor has a lower-run horizontal drag portion having relatively thin flat product-conveying paddles in contact with said product and liquid and an upper return run portion above said product and liquid;    c. said paddles being spaced apart along the conveyor and projecting radially outward and laterally thereof, and said paddles further having outer edges thereof closely conforming to the shape and size of the bottom and side wall configuration of said trough whereas to be in essentially intimate contact with the trough bottom and at least upwardly-extending portions of said side walls at least adjacent to the bottom wall;    d. introducing product and liquid into said trough at said inlet end to a level approximating the depth of said paddles when they are in contact with the trough bottom;    e. maintaining the product and liquid in discrete batches separated only by the thickness of the paddles as the batches move in a relatively continuous non-agitated flow along said trough;    f. operating the continuous conveyor at a predetermined speed in relation to the length of the trough between the inlet end and the liquid extraction section whereby to provide a predetermined residence time of the product in said liquid prior to its extraction;    g. providing said liquid extraction section in the form of a drain screen having an upper surface coplanar with said trough bottom wall, and gravitationally extracting liquid from each batch of product during passage of the batch over said screen; and    h. discharging product from the outlet end after completion of the extraction.    
   
   
       2 . The method according to  claim 1  including the step of maintaining a downward restraint against said paddles toward the trough bottom at least between the inlet end and extraction section in order to maintain the paddles edges is said intimate contact, said contact damming and essentially sealing each product and liquid batch against liquid flow between adjacent batches.  
   
   
       3 . The method according to  claim 1  wherein said liquid comprises water and wherein said method further includes the step of recirculating the liquid from said extraction section to said inlet end.  
   
   
       4 . The method according to  claim 3  wherein said particulate product comprises a vegetable or fruit that has been reduced in size to less than whole.  
   
   
       5 . The method according to  claim 4  wherein said liquid further includes calcium chloride and wherein said product is diced tomatoes.  
   
   
       6 . The method according to  claim 4  wherein said product is cut baby carrots.  
   
   
       7 . The method of continuously conveying discrete batches of a particulate product immersed in a treating liquid for a predetermined time period and extracting the liquid from the product during the conveyance, comprising the steps of: 
 a. providing an elongated horizontal stationary watertight trough having a product and liquid inlet end, a product discharge end remote from the inlet end and a liquid extraction section intermediate said inlet and discharge ends, said trough having a bottom wall and opposing upwardly and outwardly-extending side walls for the length thereof;    b. segregating said discrete batches from one another with spaced-apart relatively thin flat product-conveying paddles having sides in contact with said product and liquid and having edges in relatively intimate contact with said bottom and side walls;    c. introducing product and liquid into said trough at said inlet end to a level approximating the depth of said paddles when they are in contact with the trough bottom;    d. driving said paddles at a predetermined uniform speed in relation to the length of the trough between the inlet end and the liquid extraction section whereby to provide a predetermined residence time of the product in said liquid prior to its extraction;    e. gravitationally extracting liquid from each batch of product during passage of the batch over said extraction section; and    f. discharging product from the outlet end after completion of the extraction.    
   
   
       8 . The method according to  claim 7  including the step of maintaining a downward restraint against said paddles toward the trough bottom at least between the inlet end and extraction section in order to maintain the paddles edges is said intimate contact, said contact damming and essentially sealing each product and liquid batch against liquid flow between adjacent batches.  
   
   
       9 . The method according to  claim 7  wherein said liquid comprises water and wherein said method further includes the step of recirculating extracted liquid from said extraction section to said inlet end.  
   
   
       10 . The method according to  claim 9  wherein said liquid further includes calcium chloride and wherein said product is diced tomatoes.  
   
   
       11 . In a drag conveyor for en masse moving of particulate product and liquid in continuous discrete batches and extracting the liquid from the product during movement: 
 a. said conveyor comprising an elongated horizontal watertight trough having an inlet end for introducing product and liquid thereinto, a product discharge end and a liquid extraction section situated intermediate said ends;    b. said trough further having an inner end wall adjacent said inlet end, an inner bottom wall and a pair of opposing upwardly and outwardly-extending inner side walls;    c. said liquid extraction section comprising a horizontal drain screen mounted in said bottom wall with the upper surface thereof in coplanar alignment with said bottom wall and further having drain openings therethrough;    d. a continuous chain mounted for travel in a vertical plane within and above the trough from said inlet end to a location beyond said discharge end, said chain being supported on a horizontal axis drive sprocket adjacent the discharge end and a horizontal axis driven sprocket adjacent the inlet end;    e. a plurality of relatively thin, flat radially-outward extending product-conveying paddles carried by and spaced along said chain, all of said paddles being of the same lateral shape and dimensions with the radially-outward and side edges thereof being the same size and configuration as said inner trough bottom wall and side walls whereby to maintain relatively intimate contact with the bottom wall and at least a portion of each side wall extending upwardly from the bottom wall;    f. a motor for driving said drive sprocket and chain with a lower run of said paddle edges contacting the bottom and side walls as the chain moves them through the trough, whereby liquid and product entering the inlet end are substantially maintained as discrete product batches between retention dams formed by adjacent paddles;    g. a fixed-position elongated holddown surface adjacent each inner side wall and extending the length of said trough, said holddown surfaces being positioned to be contacted by radially-inner edges of said paddles as they traverse the trough in order to maintain the outer edges of said paddles in intimate contact with said bottom wall; and    h. the drain openings in said drain screen and the speed of the motor and chain being so interrelated as to provide sufficient time to drain liquid from the product during passage of the product over the liquid extraction section.    
   
   
       12 . In a drag conveyor according to  claim 11 , liquid-conducting conduit extending between said liquid extraction section and said inlet end for enabling recirculation of extracted liquid to be redirected to said inlet end for reuse.  
   
   
       13 . In a drag conveyor according to  claim 11 , a cover extending over the trough for its full length, and a plurality of pressurized spray wash elements within the trough and spaced at various locations therealong whereby, upon completion of conveying a given product, the drag conveyor may be continued in operation for a period of time sufficient to enable complete cleaning of the entirety of the trough, chain and paddles by means of the spray and the self-cleaning contact of the bottom of the trough by said paddle edges.